Geochronology, geochemistry and tectono-magmatic evolution of the upper Carboniferous-lower Permian Kula pluton in the Istranca (Strandja) Massif, NW Turkey

Abstract

Upper Carboniferous-lower Permian plutonic rocks (i.e. the Kula pluton) are exposed in Istranca (Strandja) Zone, NW Pontides on both sides of Turkish and Bulgarian border. The Kula pluton is composed of monzogranite, granodiorite, and quartzmonzodiorite facies with a medium to coarse-grained, mylonitic-blasto mylonitic texture. It was affected by low-grade greenschist facies metamorphism, and displays distinct foliation as a result of intense tectonism. This pluton was classified as metaluminous and peraluminous (ASI values 0.95-1.13), I-type, calc-alkaline to high-K calc-alkaline in character. Zircon U-Pb crystallization ages of the pluton are between 298.0.6 +/- 0.68 Ma (early Permian - Asselian) and 311.91 +/- 1.34 Ma (late Carboniferous - Moscovian). Based on new geochemical and geochronological data, the Kula pluton was generated from a subduction-related magmatic arc-setting during the late Carboniferious to early Permian. This period corresponds to the closure of the Paleo-Tethys Ocean following northward subduction of the Paleo-Tethyan oceanic lithosphere and development of a magmatic arc along the Eurasian continental margin.